Bacterial Speck
Risk near you, next 48h
See whether your local forecast favours this disease right now.
When it strikes
Treat, then re-check in 5–7 days
Pick off the worst material, apply the organic option below, and look again after five to seven days. If the spread continued, escalate rather than repeating the same treatment.
Rain and irrigation splash
Water splashing off soil and infected leaves carries it upward and along the row. Watering at the base and mulching the soil surface break the route.
It carries over to next season in soil, debris or seed — which is why rotation matters here, not just treatment.
Keep out of the compost
This survives a garden heap. Bag it for municipal green waste, which is composted industrially at temperatures a garden heap cannot reach, or burn it where that is permitted.
When and where to look
Scout the planting while temperatures hold between 13°C and 25°C, with humidity above 80%, after rain or heavy dew, while the leaves are still wet. Risk builds after roughly 6 unbroken hours of those conditions, so the morning after such a night is the moment to look.
The signs that lead here
About
Bacterial speck (Pseudomonas syringae pv. tomato) is a cool, wet-weather tomato disease that blemishes fruit and spots foliage, most damaging early in the season and in spring transplants.
Symptoms
Tiny dark brown to black specks with narrow yellow halos on leaves, stems and especially fruit, where they stay small and superficial but downgrade quality.
Organic Treatment
Remove infected debris, avoid overhead watering, and apply copper preventively in cool wet spells. Use clean seed.
Chemical Treatment
Copper plus mancozeb on a preventive schedule during cool wet weather.
Prevention
Use certified seed and transplants, rotate, mulch, water at the base, and avoid handling wet plants.
Related problems
Bacterial Speck risk by location
Each location has a month-by-month profile computed from the weather archive: how many hours a year actually meet this disease’s thresholds.